Diisopropylamine → 5-Formyl-3-(2,2,2-trifluoroacetylamino)thiophene-2-carboxylic acid methyl ester

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Reaction Conditions

Reaction Steps

A 1.6M n-BuLi solution in hexane (12 mL) was added dropwise to a solution of diisopropylamine (2.9 mL) in THF (30 mL) at −78° C. The reaction mixture was stirred at 0° C. for 10 min and then cooled to −78° C., and a solution of 3-(2,2,2-trifluoroacetylamino)thiophene-2-carboxylic acid methyl ester (1.5 g) in THF (15 mL) was added. The reaction mixture was stirred at −78° C. for 30 min and then 1-formylpiperidine (4 g) was added, and the mixture was again stirred at this temperature for 1.5 h. Subsequently, saturated ammonium chloride solution was added and the reaction mixture was allowed to reach room temperature. The aqueous phase was extracted several times with ethyl acetate. The combined organic phases were dried over sodium sulfate and the solvent was removed in vacuo. The product with the molecular weight of 281.0 (C9H6F3NO4S) was obtained in this way; MS (ESI): 282 (M+H+).

Provenance & Evidence